n=int(input())
cnt=[0]*11
for _ in range(n):
    a,b,c=map(int,input().split())
    cnt[a]+=1;cnt[b]+=1;cnt[c]+=1
x=0;y=0
for i in range(11):
    x+=cnt[i]>>1
    y+=cnt[i]&1
print(x+y//4)